An important consideration in the design of radar systems, particularly those for military applications, is the provision of means for minimizing the effects of hostile stand-off (mutual support) jamming either main lobe or side lobe.
Many techniques have been used to minimize the effects of such hostile jamming including side-lobe cancelling techniques. The side-lobe cancellers reduce interference in antenna side lobes while not improving any interference in the main lobe. The side-lobe cancellers are also relatively costly since extensive modification must be made to a radar installation including the addition of another antenna and receiver. Furthermore, the side-lobe cancellers require a separate loop for each jammer.
It has also been found that the large fluctuation in jamming power versus frequency occur very rapidly and the effects of these variations will be different when measured from two different antennas. The prior art apparatus, thus, cannot take advantge of the fast fluctuations and also measures jamming with an antenna that is not seeing the true jamming entering the radar.